* TODO fix notebook [20%]
** DONE https://github.com/herth/ltk/pull/2/commits/64cb7e86519749c9f212729ab28af92c628315aa
** TODO notebook-insert
** TODO notebook-instate
** TODO notebook-state
** TODO notebook-tabs
** optimize pixmap loading
   (probably the bottleneck is data -> tk list conversion, no profiling performed though)
